Method and apparatus for radio resource allocation in a wireless communication system

ABSTRACT

A method and apparatus for re-allocating radio resources in a wireless communication system includes observing an original allocation of radio resources within the system. The method collects system statistics over an observation interval, determines an optimal allocation of radio resources based on the observed statistics, and re-allocates the radio resources based on the determination.

CROSS REFERENCED TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/716,430, filed on Sep. 13, 2005, which is incorporated by referenceherein as if fully set forth.

FIELD OF INVENTION

The present invention relates to wireless communications. Moreparticularly, the present invention relates to a method and apparatusfor radio resource allocation in a wireless communication system.

BACKGROUND

Wireless communication systems employ various multiple access schemes inorder to support the call load of multiple users. In such multipleaccess schemes, a number of radio resources or radio channels areavailable for communication between the Radio Access Network (RAN) andusers. When a call is requested, radio resources are allocated from apool of available resources for the duration of the call. When the callends, the radio resources are re-inserted into the pool of availableresources so that they may be allocated to other calls.

A Dynamic Channel Allocation (DCA) function is generally responsible forallocating radio resources when a call is requested. Sophisticated DCAmethods determine an optimal allocation of resources amongst a set ofavailable resources, such that certain system metrics are optimized. Byway of example, typical system metrics include power consumption andinterference.

When allocating system resources, the set of available resources for aparticular request does not necessarily consist of all available systemresources. For example, in Time Division Duplex (TDD) systems, a certainnumber of timeslots per frame are allocated for downlink (DL)transmission whereas the remainder are allocated for uplink (UL)transmission. In this case, DCA must restrict its choice for radioresources to DL timeslots for DL requests and to UL timeslots for ULrequests. Similarly, a network operator might want to allocate radioresources for particular services. For example, in TDD systems, certaintimeslots could be allocated for real time (RT) services whereas othertimeslots could be allocated for non-real time (NRT) services.

In other types of wireless systems, the radio resources that areallocated for specific services could be frequency bands, channelizationcodes, timeslots, power units, and the like.

Ordinarily, radio resources cannot be straightforwardly divided betweenservice types and direction because they have different requirements.Additionally, a number of characteristics are typically service-typeand/or direction dependent. For instance, an offered load is the numberof calls requested and the data rate of the requests. A call blockingrate is the rate at which call requests are blocked because radioresources are unavailable. A call dropping rate is the rate at whichactive calls prematurely end, such as due to a bad connection. Usersatisfaction is the percentage of users for which Quality of Service(QoS) requirements are met. QoS requirements include BLER (Block ErrorRate), transmission delay and the like.

Data calls typically have a higher DL data rate than UL data rate. Thisis a result of the fact that user downloads typically far exceeduploads, causing a higher DL traffic load and asymmetric traffic.Similarly, RT calls typically have different QoS, call blocking and calldropping requirements than do NRT calls. Moreover, the radio resourcesto be allocated do not necessarily offer the same capacity to eachservice-direction combination. For example, in TDD systems, one timeslotmight support more UL RT calls than DL RT calls, or vice versa. As aresult, an operator cannot simply allocate twice as many timeslots forDL transmission if the DL offered load is twice the UL offered load.

Given these service-type and/or direction dependent requirements,determining the optimal allocation of available radio resources becomesa complex problem.

It would therefore be beneficial to determine an optimal allocation ofradio resources without the limitations of the prior art.

SUMMARY

A method and apparatus for re-allocating radio resources in a wirelesscommunication system includes observing an original allocation of radioresources within the system. The method collects system statistics overan observation interval, determines an optimal allocation of radioresources based on the observed statistics, and re-allocates the radioresources based on the determination.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiments of the present invention will be betterunderstood when read with reference to the appended drawings, wherein:

FIG. 1 is a block diagram of a wireless communication system configuredin accordance with the present invention;

FIG. 2 is a representative radio frame structure prior to the allocationof timeslots;

FIG. 3 is a modified radio frame structure after timeslots have beenre-allocated;

FIG. 4 is a flow diagram of a method of determining an optimalallocation of timeslots in a wireless communication system; and

FIG. 5 is a flow diagram of a method of re-allocating timeslots in thewireless communication system of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereafter, a wireless transmit/receive unit (WTRU) includes but is notlimited to a user equipment, mobile station, fixed or mobile subscriberunit, pager, or any other type of device capable of operating in awireless environment. When referred to hereafter, a base stationincludes but is not limited to a Node-B, site controller, access pointor any other type of interfacing device in a wireless environment.

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 1 is a block diagram of a wireless communication system 100configured in accordance with the present invention. The wirelesscommunication system 100 includes a plurality of WTRUs 110, a radionetwork controller (RNC) 120, and a base station 150, capable ofwireless communication with one another.

The RNC 120 is configured to observe and re-allocate radio resources inthe wireless communication system 100 in accordance with the presentinvention. The RNC 120 includes a processor 121 configured to observeand re-allocate radio resources in the wireless communication system100, and a memory 124 in electrical communication with the processor121.

The base station 150 includes a receiver 122 and a transmitter 123, bothcapable of communication with the RNC 120. The base station 150 alsoincludes an antenna 125 in electrical communication with both thereceiver 122 and the transmitter 123 to facilitate transmitting andreceiving information wirelessly.

FIG. 2 is a representative radio frame structure 200 in the wirelesscommunication system 100. The radio frame structure 200 includes aplurality of radio resources 205, which serve radio transmission needs.In a typical time division duplex (TDD) system, where the radioresources are timeslots, a typical radio frame structure 200 includes 15timeslots for transmission. As shown, a grouping of timeslots isoriginally allocated for the uplink direction for a first service (sayS1) 230, the uplink direction for a second service (say S2) 240, thedownlink direction for the first service 250, and the downlink directionfor the second service 260. A downlink to uplink direction switchingpoint 210 is provided prior to the first timeslot for uplink, and anuplink to downlink direction switching point 220 is provided prior tothe first timeslot for downlink. By way of example, S1 may represent areal time (RT) service such as a voice communication service and S2 mayrepresent a non-real time (NRT) service such as a data communicationservice, since it may be preferable to segregate RT and NRT timeslots ina TDD system.

Importantly, the original allocation of resources in FIG. 2 may not bethe optimal allocation of resources for the radio frame structure 200.For example, FIG. 2 shows 6 timeslots allocated for S1-UL (230), 2timeslots for S2-UL (240), 4 timeslots for S1-DL (250), and 3 timeslotsfor S2-DL (260). Accordingly, if more than 6 timeslots are required forS1-UL and less than 4 timeslots are required for S1-DL, then the radioframe 200 will not be optimally serving users requesting resources.

FIG. 3 is a modified radio frame structure 300 after the RNC 120 hasobserved the radio frame structure 200 and re-allocated timeslots tooptimally service user requests. The representative radio framestructure 300 depicted is only representative and it is to be noted thatalternative allocations should be apparent to one of ordinary skill inthe art.

In the present allocation of the modified radio structure 300, the radioframe structure 200 is modified to more effectively serve usersrequesting resources. For example, the original allocation of timeslotsfor S1-UL (230) was 6. In the present example, the processor 121 of theRNC 120 has determined that only 4 timeslots for S1-UL were needed(330). Additionally, in the original allocation for radio framestructure 200, the number of timeslots allocated for S2-UL (240) was 2.In the present example, the number of timeslots allocated for S2-UL is 1(340). Whereas 4 timeslots were allocated for S1-DL (250) in the radioframe structure 200, the processor 121 of the RNC 120 has reallocated 5timeslots for S1-DL (350), and 5 timeslots for S2-DL (260). Similarly tothe radio frame structure 200, the modified radio frame structure 300includes a DL-UL switching point 310 prior to the first timeslot, and arelocated UL-DL switching point 320.

The changes in allocation from the radio frame structure 200 to themodified radio frame structure 300 may be attributed to the statisticsobserved by the RNC 120, and the re-allocation of resources by theprocessor 121 of the RNC 120. More particularly, using the examplewherein S1 is a voice service and S2 is a data service, the modifiedradio frame structure 300 may reflect the needs of voice users and datausers. That is, after the performance of the method 500 (shown in FIG.5), it may have been determined that more timeslots were needed fordownlink services (S1-DL and S2-DL) then uplink services, and that datauplink (S2-UL) required only one timeslot as opposed to data downlink(S2-DL) which required 5 timeslots. In a practical sense, this could bethe result of higher downlink service use by a user than uplink use fordata.

FIG. 4 is a flow diagram broadly showing a method of determining anoptimal configuration of timeslots 400. In the present example, themethod 400 observes and determines the configuration of timeslots forthe two different services, S1 and S2, both in the UL and DL directions,and optimally re-allocates the timeslots.

In step 410, an initial allocation of radio resources is made to thewireless communication system 100. In a preferred embodiment of thepresent invention, a network operator allocates resources to eachservice as the network operator desires prior to observing the system inoperation.

In step 420, statistics are collected for the wireless communicationsystem 100 by observing the system for the period of time that thesystem operator chooses. This period might be one day, one week, severalweeks, one month, several months, or any other time period known to oneof ordinary skill in the art.

In a preferred embodiment of the present invention, the RNC 120 observesthe wireless system 100 by receiving data about the system from thereceiver 122 and antenna 125 of the base station 150. In a preferredembodiment of the present invention, statistics such as rejectedresource units may be observed within the processor 121 of the RNC 120,while other statistics, such as dropped resource units are observed atthe base station 150. The receiver 122 of the base station 150 transfersthis data to the processor 121 of the RNC 120, which then stores all ofthe data about the present allocation in the memory 124 of the RNC 120for later extraction.

In particular, to facilitate the re-allocation of resources, thefollowing statistics are preferably observed and collected:

-   -   Rejected resource units (RUs) Q: Average number of new RU        requests that are rejected per frame.    -   Dropped RUs D: Average number of RUs that are dropped per frame.    -   Served RUs S: Average number of RUs that are served per frame.    -   Offered Load O: The sum of Served RUs, Rejected RUs and Dropped        RUs. That is:        O=Q+D+S.

The offered load O, therefore, is essentially all of the resource unitsthat are requested by users, whether served or not served. Since eitherrejected or dropped RUs are effectively unserved units, the method ofre-allocating resources will endeavor to limit the values of D and Q,while maximizing the value of S. Accordingly, in an optimal radio framestructure, it is desirable that all resource units be served resourceunits, so that users' communication needs are met.

Although the average number of RUs per frame is utilized as an inputherein, the percentile of the number of RUs could be considered insteadof averages. For example, the 95^(th) percentile of the number of RUsthat are served per frame could be used rather than the average numberof RUs that are served per frame. The percentile can be easilycalculated from performance metrics Q, D, S and O extracted from the RNC120. The individual service and direction statistics collected are thencombined in order to obtain overall statistics per transmissiondirection (DL or UL) or per service type (S1 or S2). In a preferredembodiment of the present invention, the statistics are observedindividually for each service and direction prior to re-allocatingresources. For example, again referring to FIG. 2, the statistics areobserved for the first service (S1) in both the downlink (DL) and uplink(UL) directions and for the second service (S2) in both the DL and ULdirections. However, any number and type of services known to one ofordinary skill in the art may exist and be observed.

Based on the above collected statistics, the processor 121 can thendetermine the optimal allocation of timeslots within a radio frame foreach service and direction and re-allocate the resources accordingly(step 430). Moreover, since the timeslot requirements for S1 and S2 maybe significantly different, the re-allocation of timeslots shouldreflect those needs. For example, the network operator may wish toprioritize the needs of S1 above the needs of S2, or vice versa. Thismay be achieved during the re-allocation of timeslots by theintroduction of a weighting constraint, which will be described in moredetail below.

After re-allocating radio resources in step 430, the RNC continues tocollect statistics over the observation period (step 420), and tore-allocate radio resources (step 430) as required.

FIG. 5 is a flow diagram of a method of re-allocating timeslots 500 inthe wireless communication system 100, in accordance with the presentinvention.

In step 510, the network operator initializes the number of timeslotsassigned to each service to the minimum number. For example, in thewireless communication system 100 of the present example, there are 4services. Therefore, if the network operator wished to ensure that atleast one timeslot was allocated for each service i, the minimum numberof timeslots N_(i) ^(MIN) might be set to 1. Accordingly, 1 timeslotinitialized for each of the 4 services would ensure that 4 timeslots areallocated. Since a typical radio frame contains 15 total timeslots, thiswould generate 11 timeslots to re-allocate.

Notwithstanding the specific number of timeslots to re-allocate, givenany number of timeslots N for dedicated channels, the re-allocation forN_(S1-DL), N_(S2-DL), N_(S1-UL), and N_(S2-UL) can be determined usingthe following constraint:N=N _(S1-DL) +N _(S1-UL) +N _(S2-DL) +N _(S2-UL).

That is, the total number of timeslots to be served (N) must take intoaccount each different service, as well as each direction. In thepresent example, there are four services requiring timeslotre-allocation.

In order to simplify the service and direction combinations, an indexingnotation may be considered, given by the following equation:$N = {\sum\limits_{i = 1}^{NS}N_{i}}$

This notation utilizes the mapping between service-direction and indexnumber i (representing a service/direction combination) that is given inTable 1. The variable N_(i) represents the number of timeslots that areallocated for a service i, and the constant NS represents the number ofservices for which the total number of timeslots N are to be allocated.In the present example, NS=4 for service one/downlink (S1-DL), serviceone/uplink (S1-UL), service two/downlink (S2-DL), and service two/uplink(S2-DL). More particularly, i(1) represents S1-DL, i(2) representsS1-UL, i(3) represents S2-DL, and i(4) represents S2-UL. TABLE 1 Mappingbetween index number and service type and direction Service Type and iDirection 1 S1-DL 2 S1-UL 3 S2-DL 4 S2-UL

In step 520, the processor 121 of the RNC 120 determines whether or notthere are any timeslots for any service i that require allocating. Ifthere are not, then the method 500 ends at step 590.

However, in the case where not enough timeslots have been assigned to aservice i so as to serve its offered load, O_(i) the proportion of theoffered load that is not served per frame is calculated (R_(i)) (step530). Therefore, R_(i) represents the relative number of RUs that arerejected or dropped at each frame. This is calculated by dividing theoffered load of service i per frame into the offered load of service iper frame minus the product of the configuration parameter K_(i) and thenumber of timeslots that are allocated for the service i. The equationrepresenting this instance is as follows:$R_{i} = {\frac{O_{i} - {K_{i} \times N_{i}}}{O_{i}} = {1 - \frac{K_{i} \times N_{i}}{O_{i}}}}$

In order to calculate the value of R_(i), the following inputs andparameters need to be defined:

-   -   N_(i) ^(MIN): The minimum number of timeslots to be assigned for        service i.    -   N_(i) ^(PREV): The previous number of timeslots that were        allocated for service i.    -   Q_(i): The average number of rejected RUs of service i per        frame.    -   S_(i): The average number of RUs of service i that are served        per frame.    -   O_(i): The offered load of service i per frame, which is the sum        of observed served RUs, rejected RUs and dropped RUs statistics        of service i.    -   K_(i): The number of RUs of service type i that can be served in        one timeslot.

The previous number of timeslots (N_(i) ^(PREV)) for a service i is thenumber of timeslots that were allocated for that particular service inany previous iteration of the method 500. Again using the presentexample, if the network operator wished to begin by allocating at leastone timeslot per service i, then N_(i) ^(MIN) should be equal to 1 forany service i at the start of the implementation of the method 500.

The configuration parameter K_(i) then, is the number of RUs of servicetype i that can be served in one timeslot, and can be determined asfollows. If the average number of rejected RUs of each service i perframe is greater than zero (Q_(i)>0), then the offered load per framefor each service i is greater than the number of resources that wereallocated for that service. That is, not enough resources were allocatedto serve that particular service.

Therefore, in this scenario, the configuration parameter K_(i) is set tothe average number of RUs that were served per timeslot. This can becalculated by dividing the average number of RUs of the service i thatare served per frame S_(i) by the number of timeslots that wereallocated for the service i (N_(i) ^(PREV)) as demonstrated by thefollowing equation: $K_{i} = {\frac{S_{i}}{N_{i}^{PREV}}.}$

On the other hand, if the average number of rejected RUs of service iper frame is less than zero (Q_(i)<0), then the offered load per framefor service i is smaller than the number of resources that wereallocated for service i. Accordingly, the average number of RUs ofservice i that are served per frame S_(i) does not accurately representthe number of RUs of service i that can be served in one timeslot.Therefore, the parameter K_(i) is set to a constant value that isprovided by the network operator as an input, K_(i)′. The networkoperator can set the configuration parameter to a value he deemsappropriate based on the observed statistics, or can use any otherparameters known to one of ordinary skill in the art.

Here, R_(i) corresponds to the probability that an offered RU is notserved. This can be referred to as the non-served probability. There-allocation in this case should therefore attempt to minimize R_(i)for all services i.

For example, suppose that the offered load O_(i) for a particularservice i is 10 RUs, but only 2 timeslots were allocated (N_(i)=2), andit is observed that the system can handle 4 RUs per timeslot (K_(i)=4).In this example, the non-served probability R_(i) would equal 2/10ths,or 20%. Therefore, two out of the 10 RUs will go unserved.

If R_(i) is greater than zero in step 540, then the method 500determines the service i for which R_(i) is the greatest (step 550)taking into account a weighting constraint defined as follows:α_(i) ×R _(i) =α _(j) ×R _(j) for all i and jIn this equation, α_(i) is used to prioritize between different servicestypes and the weighted non-served probability of each service typeshould be equal in the final allocation. Additionally, the variable j isintroduced as the service i for which the method 500 will allocate thetimeslot. The weighting factors, α_(i) may be obtained by comparing thecall rejection probability and call dropping probability requirements ofeach service. Higher priority service types should have higher values ofα_(i). For example, voice services may be more critical to the networkoperator than data services. Therefore, the network operator may wish toplace a greater weight toward assuring that resources are allocated forvoice service than data service, notwithstanding data service needs.Additionally, the DL and UL of the same service should have the samecall blocking and call dropping requirements. Referring again to Table1, it can be seen that α₁=α₂ and α₃=α₄. Absolute values of α_(i) are notimportant, only relative values of α_(i) should be determined.

In step 550, the method 500 determines which service has the highestproportion of offered load that is not served, so as to determine whichservice will be allocated an additional timeslot. Therefore, arepresentative equation for the processor 121 to determine the service jfor which to allocate the timeslot is:j=arg_(i) max(α_(i) ×R _(i))

After determining which service j to allocate the timeslot to (step550), the processor 121 allocates the timeslot in step 580 (Nj=Nj+1) andthe method 500 returns to step 520 to determine whether or not any moretimeslot exist to be allocated.

Moreover, in a TDD system, an integer number of timeslots must beassigned to each service and direction combination since it is notpossible to allocate partial timeslots. Therefore, aninteger-constrained optimization problem arises to allocate thetimeslots. This can be solved, in a preferred embodiment of the presentinvention, by employing an iterative method for determining theallocation. That is, one timeslot is allocated in step 580 to a servicej at each iteration of the method 500, ensuring that an integer numberof timeslots is assigned to each service and direction combination.

If in step 540, the processor determines there are enough timeslots toserve the offered load of all i's, that is, where timeslots are abundant(R_(i)≦0), then the processor 121 calculates an extra capacity metricE_(i) that is allocated to service i at each frame (step 560). This canbe represented as the equation:$E_{i} = {\frac{{K_{i} \times N_{i}} - O_{i}}{O_{i}} = {\frac{K_{i} \times N_{i}}{O_{i}} - 1}}$E_(i) corresponds, in this formula, to the ratio of the number of extratimeslots that are allocated for a service i to the offered load of theservice i. When timeslots are abundant, the method of allocating shouldattempt to maximize E_(i) for all services i.

In similar fashion to the case where timeslots are not abundant, asecond weighting constraint can be defined as:β_(i) ×E _(i)=β_(j) ×E _(j) for all i and j.

Again, the weighted extra capacity of each service type should be equalin the final allocation. The weighting factors, β_(i), are obtainedsimilarly to α_(i). Higher priority service types should have smallervalues of β_(i). Moreover, in the present example of S1 and S2, DL andUL, β₁=β₂ and β₃=β₄, as in the previous case. Once again, since theabsolute values of β_(i) are not important, only the relative values ofβ_(i) should be determined.

In step 570, the method 500 determines which service has the lowestextra capacity metric, so as to determine which service to allocate anadditional timeslot. Therefore, a representative equation for theprocessor 121 to determine the service j for which to allocate thetimeslot is:j=arg_(i) min(β_(i) ×E _(i))

After determining which service j to allocate the timeslot to (step570), the processor 121 allocates the timeslot in step 580 (Nj=Nj+1) andthe method 500 returns to step 520 to determine whether or not any moretimeslots exist to be allocated.

As previously described, the method of allocating timeslots 500 ends(step 590) once all of the timeslots are allocated.

The re-allocation of timeslots may be transmitted to the WTRUs 110 bythe processor 121 of the RNC 120 through the transmitter 123 and theantenna 125 of the base station 150.

While the invention is described for TDD systems, where timeslots arethe resources to be allocated, the invention may be implemented in anysystem that benefits from allocation of resources, including, but notlimited to: FDD, TDSCDMA, OFDM, UMTS, CDMA, CDMA 2000. In a preferableexample, according to a TDD system, timeslots are allocated for UL andDL transmission for two different services, defined as service one (S1)and service two (S2), although allocation can be performed for anynumber of services known to one of ordinary skill in the art. Similarly,it can be simplified to only allocating timeslots for UL and DLtransmission, independently of the service type. The proposed method canalso be adapted to other types of systems where codes, timeslots, powerunits, or any combination thereof are to be allocated.

The method can determine the allocation of resources for any cluster ofcells in the network, ranging from one cell to the entire radio accessnetwork. The resulting configuration determined in the method should beapplied to all cells within the cluster. To adequately perform themethod of allocating resources, the system statistics should becollected for the entire cluster of cells over an extended period oftime, prior to invoking the method, and should be averaged on aframe-basis over the entire observation interval. The observationinterval can correspond to the time between two invocations of themethod, or any other interval of time. For example, the method mightonly consider statistics observed during a peak congestion period inorder to optimize the resource configuration for that period of time.

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone (without the other features andelements of the preferred embodiments) or in various combinations withor without other features and elements of the present invention. Forexample, in a preferred embodiment of the present invention, the methodsof observing and re-allocating resources are described as beingperformed by a processor, preferably with an application running on theprocessor to perform the methods. However, any method known to one ofordinary skill in the art may be utilized to perform the method ofobserving and allocating resources in the wireless communication system.For example, the features of the present invention may be incorporatedinto an integrated circuit (IC) or be configured in a circuit comprisinga multitude of interconnecting components. Additionally, the method ofobserving and re-allocating resources is applicable to the applicationlayer of wireless systems; and may be implemented as software ormiddleware.

1. A method for allocating radio resources in a wireless communicationsystem comprising a plurality of wireless transmit/receive units(WTRUs), a base station, and a radio network controller (RNC) incommunication with one another, the method comprising: observing anoriginal allocation of radio resources within the system; collectingsystem statistics over an observation interval; determining an optimalallocation of radio resources based on the observed statistics; andre-allocating radio resources based on the determination.
 2. The methodof claim 1, further comprising the step of assigning an initialallocation of radio resources to the system.
 3. The method of claim 2,wherein the radio resources allocated are timeslots.
 4. The method ofclaim 3, wherein the timeslots are allocated for a first service.
 5. Themethod of claim 4, wherein the timeslots are allocated for a firstdirection of the first service.
 6. The method of claim 5, wherein thetimeslots are allocated for a second direction of the second service. 7.The method of claim 4, wherein the timeslots are allocated for a secondservice.
 8. The method of claim 7, wherein the timeslots are allocatedfor a first direction of the second service.
 9. The method of claim 8,wherein the RNC determines whether any timeslots remain to be allocated.10. The method of claim 9, wherein the RNC observes the previous numberof timeslots that were reserved for each of the first and secondservices, the average number of resource units not served, and theaverage number of resource units served.
 11. The method of claim 10,wherein the RNC calculates an offered load.
 12. The method of claim 11,wherein the offered load is the sum of the average number of resourceunits not served and the average number of resource units served. 13.The method of claim 11, wherein the RNC calculates the number ofresources that can be served in one timeslot.
 14. The method of claim13, wherein the number of resources that can be served on one timeslotis the previous number of timeslots that were reserved divided into theaverage number of resource units served.
 15. The method of claim 13,wherein the RNC calculates a proportion of offered load that is notserved for the first and second services.
 16. The method of claim 15,wherein the proportion of offered load that is not served is greaterthan zero.
 17. The method of claim 16, wherein the RNC determines whichservice has the greatest proportion of offered load not served.
 18. Themethod of claim 17, wherein the RNC includes a weighting factor todetermine which service has the greatest proportion of offered load notserved.
 19. The method of claim 16, wherein the RNC allocates anadditional timeslot to the service which has the greatest proportion ofoffered load not served.
 20. The method of claim 15, wherein theproportion of offered load not served is less than or equal to zero. 21.The method of claim 20, wherein the RNC calculates an extra capacity foreach service.
 22. The method of claim 21, wherein the RNC determineswhich service has the lowest extra capacity.
 23. The method of claim 22,wherein the RNC includes a weighting factor to determine which servicehas the lowest extra capacity.
 24. The method of claim 22, wherein theRNC allocates an additional timeslot to the service which has the lowestextra capacity.
 25. The method of claim 1, wherein the step ofdetermining the optimal allocation of radio resources is performedperiodically over a pre-determined time period.
 26. The method of claim25, wherein the time period is one day.
 27. The method of claim 25,wherein the time period is one week.
 28. The method of claim 25, whereinthe time period is one month.
 29. The method of claim 1, wherein thestep of determining the optimal allocation of radio resources isperformed at a specific time.
 30. In a wireless communication systemcomprising a plurality of wireless transmit/receive units (WTRUs), abase station, and a radio network controller (RNC) in communication withone another, the RNC comprising: a memory; and a processor incommunication with the memory, said processor configured to observeresource statistics communicated from the base station, determine anoptimal allocation of resources based on the observed resourcestatistics, and re-allocate resources to the WTRUs.
 31. The RNC of claim30, wherein the processor stores the observed resource statistics in thememory of the RNC.
 32. The base station of claim 31, further comprisinga transmitter, a receiver, and an antenna in communication with thetransmitter and the receiver.
 33. In a wireless communication systemcomprising a plurality of wireless transmit/receive units (WTRUs), abase station, and a radio network controller (RNC) in communication withone another, the RNC including an integrated circuit (IC) comprising: amemory; and a processor, in communication with the memory, wherein anapplication runs on the processor, the processor observes resourcestatistics of the system communicated from the base station, theprocessor determines an optimal allocation of resources based on theobserved resource statistics, and the processor re-allocates resourcesto the WTRUs.
 34. The IC of claim 33, wherein the processor stores theobserved resource statistics in the memory of the IC.
 35. The basestation of claim 33, further comprising a transmitter, a receiver, andan antenna in communication with the transmitter and the receiver.